Sengeløv H
Department of Hematology L-4041, Rigshospitalet, Copenhagen, Denmark.
Crit Rev Immunol. 1995;15(2):107-31.
Human neutrophils contain numerous intracellular granules and vesicles that are exocytosed in a hierarchic manner on stimulation of the neutrophil with inflammatory mediators. Secretory vesicles are mobilized completely to the plasma membrane when neutrophils are stimulated with inflammatory mediators in nanomolar concentrations. There is evidence that secretory vesicles contain at least four different complement receptors, namely, C1qR, CR1, CR3, and CR4. These complement receptors are all transported to the neutrophil surface in parallel by the mobilization of secretory vesicles. A fifth complement receptor, C5aR, is constitutively present on the neutrophil plasma membrane. Because secretory vesicles are mobilized by virtually all inflammatory mediators known to stimulate neutrophils, a prompt upregulation of complement receptors is ensured early in neutrophil activation. The integrins CR3 and CR4 are located both in secretory vesicles and granules, and this diverse subcellular localization may reflect their functional versatility. The residence of complement receptors in several intracellular compartments ensures a graded upregulation of these receptors in response to stimulation.
人类中性粒细胞含有大量细胞内颗粒和囊泡，当炎症介质刺激中性粒细胞时，这些颗粒和囊泡会以分级的方式胞吐。当用纳摩尔浓度的炎症介质刺激中性粒细胞时，分泌囊泡会完全移动到质膜。有证据表明，分泌囊泡至少含有四种不同的补体受体，即C1qR、CR1、CR3和CR4。这些补体受体都通过分泌囊泡的移动并行运输到中性粒细胞表面。第五种补体受体C5aR组成性地存在于中性粒细胞质膜上。由于分泌囊泡几乎可被所有已知能刺激中性粒细胞的炎症介质所动员，因此在中性粒细胞激活早期可确保补体受体迅速上调。整合素CR3和CR4既存在于分泌囊泡中，也存在于颗粒中，这种不同的亚细胞定位可能反映了它们功能的多样性。补体受体在几个细胞内区室中的存在确保了这些受体在受到刺激时的分级上调。
